True surface colors, near real-time (NOAA-20, 375/750 m)
What it measures. Near-real-time estimates of true surface color (surface reflectance) across many VIIRS bands, after the haze of the atmosphere has been removed, at 375 m and 750 m resolution.
How it's made. Produced from VIIRS data on the NOAA-20 satellite, with corrections for gases, water vapor, and airborne particles applied to top-of-atmosphere measurements; available quickly for daytime land scenes only.
How & where you'd use it. Because it arrives fast, it supports time-sensitive uses like monitoring vegetation, land changes, and disasters, and serves as input for many higher-level land products.
What's measured
Coverage & cadence
- Time span2023-10-10 → ongoing
- Measured byNOAA-20 (VIIRS)
- Processing levelLevel 2
- Spatial extent-180, -80, 180, 80
- FormatsHDF-EOS
- StatusACTIVE
What you can do with it
- Track deforestation, fire scars and land-cover change
- Monitor crop and vegetation health (NDVI/EVI)
- Map how built-up vs. green an area is over time
Official description
The VJ109_NRT is a Near Real Time (NRT) Visible Infrared Imager Radiometer Suite (VIIRS) 375 m, 750 m Atmospherically Corrected Surface Reflectance product. The VIIRS surface reflectance products are estimates of surface reflectance in each of the VIIRS reflective bands I1-I3, M1-M5, M7, M8, M10, and M11. The VNP09 Level-2 surface reflectance product contains approximately 6 minutes' worth of data. Surface reflectance for each moderate-resolution (750m) or imagery-resolution (375m) pixel is retrieved separately for the Level-2 products. Surface reflectance is obtained by adjusting top-of-atmosphere reflectance to compensate for atmospheric effects. Corrections are made for the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. The inputs to the surface reflectance algorithm include top-of-atmosphere reflectance for the VIIRS visible bands (VJ102MOD, VJ102IMG), the VIIRS cloud mask and aerosol product, aerosol optical thickness, and atmospheric data obtained from a reanalysis (surface pressure, atmospheric precipitable water, and ozone concentration). All surface reflectance products are produced for daytime conditions only. The product is produced under all atmospheric conditions except for night and oceans. Pixels when not produced are replaced by fill values in the Level-2 and Level-2G products. For more information read Suomi-NPP VIIRS Surface Reflectance [User's Guide](https://viirsland.gsfc.nasa.gov/PDF/VIIRS_Surf_Refl_UserGuide_v2.0.pdf)
Get the data
import earthaccess
earthaccess.login(strategy="netrc") # free Earthdata Login
results = earthaccess.search_data(
short_name="VJ109_NRT",
version="2",
bounding_box=(-122.5, 37.2, -121.8, 37.9), # your area (W,S,E,N)
temporal=("2024-01-01", "2024-12-31"), # your dates
)
files = earthaccess.open(results) # stream straight from LANCEMODISBrowsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.